Able to see correct product with 2 rounds of PCR, but my PI doesn't want me

So after 1 round of PCR, I cannot see a product with my primers. With 2 rounds, I am able to. However, my PI doesnt want me to do this because it introduces "contamination". I'm working with human samples. (limited amounts of DNA)

What PCR are you doing: MSP or BSP? For either, two rounds or nested PCR are OK. In MSP, you can first amplify the converted DNA using a pair of universal primers and then reamplify using M or U primers. For BSP, two rounds of PCR are needed for most of the times.